1. Field of the Invention
This invention relates to a method for attaching a radio frequency identification tag to an article, more particularly, a container suitable for use in a diagnostic instrument.
2. Discussion of the Art
Currently, in the area of medical diagnostics, identification of containers is generally effected by bar code labels. Bar code labels require printing onto or application onto the surface of the container. Bar code labels require an unobstructed optical path to be read, which generates design challenges for both the container and the bar code readers. The bar code label is required to be clear, i.e., the print quality must be satisfactory and the label must be clear of foreign material, such as frost resulting from humidity and storage at low temperatures. Bar code labels generally have only a limited quantity of space, with the result that the information that can be written on a bar code label is extremely limited. Bar code labels can be removed and reused, thereby leading to counterfeiting issues. Bar code labels can delaminate from the containers on account of condensation of water or low temperatures.
In the area of medical diagnostics, identification of containers by means of radio frequency identification tags and data capturing systems utilizing radio frequency identification tags can be used in order to comply with Food and Drug Administration (FDA) regulations for management of supply chains.
Radio frequency identification tags can be categorized as active, semi-passive, and passive radio frequency identification tags. The main difference between the three types of radio frequency identification tags resides in the nature of the power supply. The passive radio frequency identification tag does not require any installed power source. The passive radio frequency identification tags contain a microchip and an antenna. The minute electrical current induced in the antenna by an incoming radio frequency signal provides sufficient power to cause the microchip to transmit a response. FIG. 1 illustrates a typical radio frequency identification tag that has a microchip and an antenna.
The most critical obstacle for utilizing radio frequency identification tags is high cost. The cost of microchips associated with radio frequency identification tags is high relative to the cost of typical diagnostic products. Microchips will be expensive, unless they can be mass-produced. In addition, counterfeiting is possible by removing the radio frequency identification tag and reattaching a different radio frequency identification tag. Appearance of the container is also problematic, because attachment of radio frequency identification tags to containers results in a bumpy surface and a rough appearing surface. Still another problem is delamination of the radio frequency identification tag from the container. Finally, the scrap rate of radio frequency identification tag assembly is high on account of the difficulty inherent in the placement of a chip on the antenna contacts.
U.S. Pat. No. 6,294,998 discloses a radio frequency identification tag with a uniform profile. A compressible mask layer or cutout mask layer provides a uniform profile despite the presence of the radio frequency identification integrated circuit and antenna. The uniform profile allows clear overprinting and hinders visual detection of the radio frequency identification transponder. This radio frequency identification tag is highly susceptible to delamination from a container. U.S. Pat. No. 6,429,831 discloses a laminated label having a first conductive material defining electrical attachment pads; a dielectric material surrounding the attachment pads; a second conductive material deposited on the dielectric material and forming an antenna electrically connected to the attachment pads. A layer of expandable material forms a protective cavity surrounding the attachment pads. An IC chip is received in the protective cavity and connected to the antenna. This radio frequency identification tag is highly susceptible to delamination from a container. U.S. Pat. No. 6,548,006 discloses a plastic material injection molding machine comprising a mold having at least two mold portions and a handling system adapted to be inserted between the mold portions when the mold is in the open position, for transferring an article between the handling system and a predetermined mold portion. The device has many moving parts that are subject to wear and require a great deal of fine-tuning. U.S. Pat. No. 6,957,777 discloses a label to be attached on a plastic product formed in a mold and identifiable by a detecting device including a soft circuit board, a protective layer, and an adhesive layer. The soft circuit board has its outer layer provided with a radio frequency identification device (RFID). The protective layer is transparent, adhered on the outer surface of the soft circuit board for protecting and enabling RFID identified by a signal transmitted by a wireless detecting device. The adhering layer is made of a compound material and adhered on an inner layer for protecting the inner surface of the soft circuit board and the RFID as well. The label is attached on a plastic product during injecting molding process, widely usable for identifying an object affixed with the label by means of a detecting device. It is expected that the cost of preparing a three-layer subassembly along with the cost of a robotic handling system to place the subassembly into a mold would be high. U.S. Pat. No. 7,176,796 discloses a sealing cap with an anti-counterfeit and identification capability comprising a cap body, and identification chip with a signal emitting device generating an identification signal, and a destructive device, characterized in that the cap body is electrically connected with the signal generating device and serves as an antenna of a relatively large area and in that the destructive device after dismounting of the cap destroys the capability to emit radiation and thus prevents the identifying chip from being dismounted and reused. The radio frequency identification tag is required to be on the cap of the container. U.S. Patent Application Publication 2006/0174470 discloses a transfer resisitant RFID tag including an identification chip, a tag coil, a housing and a cap. The identification chip is electrically connected to the tag coil with two wires. A first quantity of bonding compound is applied to a surface that is slightly greater than a surface area of the identification chip. A second quantity of bonding compound is applied to the surface that is slightly greater than the end surface area of the housing. One end of the housing is attached to the second quantity of bonding compound. Then the identification chip is attached to the first quantity of bonding compound. The cap is snapped over the tag coil and the other end of the housing. If someone tries to transfer the RFID tag from one surface to another, the two wires or the identification chip will be destroyed during removal. If tampering occurs, the wires connected to the radio frequency identification tag will be destroyed, and the device will be rendered useless. U.S. Patent No. 2007/0098942 discloses a poly sheet continuously moving in a machine direction is heated to a temperature just below its glass thermal temperature to make the poly malleable. A circuit (e.g., RFID chip, EAS chip, transponder, IC) is placed on the poly sheet and embedded into the poly sheet, preferably with a heat resistant soft (e.g., rubber) roller that presses the circuit into the poly without breaking the circuit. A conductive strip or wire may be applied on or into the poly sheet to align with connection points (e.g., conductive bumps) of the circuit for conductive communication with the circuit.
In-mold decoration is known in the prior art. See, for example, U.S. Pat. Nos. 4,643,789; 4,650,533; 2006/0188595; 3,292,209; 6,117,384.
It would be desirable to develop a method for applying a radio frequency identification tag to an article, e.g., a container, in such a manner as to reduce costs, to reduce the risk of counterfeiting of the radio frequency identification tag, and to improve the appearance of the radio frequency identification tag.